This is a multi-center two-arm, randomized double-blind, controlled trial to evaluate the effect of an increased caloric density infant concentrated formula on growth and nutritional status of HIV-infected infants. An equal cohort of uninfected infants will serve as a descriptive comparison group. Newborns of HIV-infected mothers will be randomized prior to 15 days in a double-blinded design to receive either 25.7 or 20-cal/oz infant milk-based formula ad libitum. Provisional assignment of infection status for protocol purposes will be made for each enrolled subject at the eight week study visit on the basis of protocol- required virologic tests. 89% of infants with negative HIV+ tests will be discontinued from study. The other 11% will continue study treatment with open- label 20 kcal/oz study formula until 28 weeks and will continue study follow-up until 52 weeks. All infants assigned to continue study treatment beyond the eight week study visit will have repeat dietary intake, medical history, weight, length and head circumference measurements or assessments and blood specimen collection performed at the 16 week, 28 week, and 52 week study visits. At 28 weeks study treatment will be discontinued. Other food will be introduced when and as recommended by the primary care provider. Quality of life assessment will be performed at the 28 week and 52 week study visit.